Facebook said on Tuesday it is introducing new privacy controls that give users of the fast-growing social-network site the ability to preserve social distinctions between friends, family and co-workers online.

Facebook executives told reporters at the company's Palo Alto, California headquarters of changes that will allow Facebook's more than 67 million active users worldwide to control what their friends, and friends of their friends see.

The Silicon Valley company was founded in 2004 as a social site for students at Harvard University and spread quickly to other colleges and eventually into work places. Its popularity stems from how the site conveniently allows users to share details of their lives with selected friends online.

While part of Facebook's appeal has been the greater degree of privacy controls it offers users compared with other major social network sites, the site has also been the target of two major rebellions by its users in response to new features many felt exposed previously private information to wider view.

Matt Cohler, Facebook's vice president of product management, told reporters the company was seeking to evolve beyond the simple privacy controls originally aimed at relatively homogeneous groups of college-age users.

"We have a lot more users, a lot more types of users, a lot more relationships, we have a lot more types of relationships," Cohler said.

But only 25 percent of existing users have bothered to take control of their privacy using Facebook's existing personal information settings, the company said in a statement.

Use of Facebook has exploded fivefold over the past year and a half. Two-thirds of its users are now located outside the United States compared with about 10 percent 18 months ago, when most members were student age and in the United States.

Facebook members will be able to control access to details about themselves they share on the site at a group-level by creating and managing lists of friends that are granted different levels of access to such information. Users already control what individual friends see on a member's profile.

The new privacy controls will be introduced in the early morning hours of Wednesday, California time, the company said.

The group privacy controls take advantage of "friends lists," a feature the company introduced in December that help members organize friends in their network into groups. These private lists allow users to target messages to selected friends or filter what personal details those groups see.

Users can create up to 100 different "friends lists."

Late last year, Facebook allowed users to turn off a controversial feature called Beacon that monitors what Web sites they visit and Chief Executive Mark Zuckerberg apologized for not responding sooner to privacy complaints.

Beacon is a way to keep one's network of friends on Facebook informed of one's Web surfing habits. Critics argued this transformed it from a members-only site known for privacy protections into a diary of one's wider Web activities.

The company backed down in response to a petition signed by 50,000 Facebook users to scale back the Beacon feature.

Cohler said the company faces what he called a "classic Silicon Valley dilemma" between adding new features, making sure they are easier to use by the widest number of people, while also protecting members from unexpected personal revelations.

In addition, the company confirmed recent reports it is working on a new instant messaging chat feature that runs inside Facebook, allowing users to hold spontaneous back-and- forth chat with their friends on the site.

Facebook Chat, as the feature is known, will be introduced in a matter of weeks, the company said. It works inside a Web browser without requiring that users download any special software, akin to services such as Meebo.com to allow one-on- one chats.